net: dsa: felix: ignore pending status of TAS module when it's disabled

[ Upstream commit 70654f4 ]

The TAS module could not be configured when it's running in pending
status. We need disable the module and configure it again. However, the
pending status is not cleared after the module disabled. TC taprio set
will always return busy even it's disabled.

For example, a user uses tc-taprio to configure Qbv and a future
basetime. The TAS module will run in a pending status. There is no way
to reconfigure Qbv, it always returns busy.

Actually the TAS module can be reconfigured when it's disabled. So it
doesn't need to check the pending status if the TAS module is disabled.

After the patch, user can delete the tc taprio configuration to disable
Qbv and reconfigure it again.

Fixes: de143c0 ("net: dsa: felix: Configure Time-Aware Scheduler via taprio offload")
Signed-off-by: Xiaoliang Yang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

drivers/net/dsa/ocelot/felix_vsc9959.c

@@ -1474,10 +1474,13 @@ static int vsc9959_qos_port_tas_set(struct ocelot *ocelot, int port,
 	/* Hardware errata -  Admin config could not be overwritten if
 	 * config is pending, need reset the TAS module
 	 */
-	val = ocelot_read(ocelot, QSYS_PARAM_STATUS_REG_8);
-	if (val & QSYS_PARAM_STATUS_REG_8_CONFIG_PENDING) {
-		ret = -EBUSY;
-		goto err_reset_tc;
+	val = ocelot_read_rix(ocelot, QSYS_TAG_CONFIG, port);
+	if (val & QSYS_TAG_CONFIG_ENABLE) {
+		val = ocelot_read(ocelot, QSYS_PARAM_STATUS_REG_8);
+		if (val & QSYS_PARAM_STATUS_REG_8_CONFIG_PENDING) {
+			ret = -EBUSY;
+			goto err_reset_tc;
+		}
 	}
 
 	ocelot_rmw_rix(ocelot,